BERRYVILLE, Ark. — Nancy McShane abruptly quit shopping at Wal-Mart in March after her turkey-farming relatives complained about undue price pressure from the world’s largest retailer. But James Butler says the convenience and low prices outweigh any complaints.

Depending on who you ask, Americans are either sticking with Wal-Mart because of its prices and policies or turning against it amid allegations by unions and others that the company is bad for workers, the environment and communities.

The discount retailer and its critics pushed competing data to buttress both sides of the argument. According to a poll released Thursday by Wake Up Wal-Mart, an anti-Wal-Mart group launched this year by the United Food and Commercial Workers union, more Americans have an unfavorable view of Wal-Mart today than at the start of the year.

The poll showed that a majority, 58 percent, viewed Wal-Mart favorably, but the figure was down from 76 percent in January. Wake Up Wal-Mart said that was proof that its message against the company’s low-price business model is hitting its intended target — the average Wal-Mart shopper.

“It would be hard for anyone to believe that a poll paid for by the UFCW was more accurate than the fact that our estimated November store sales were up 4.3 percent and that 10 million people shopped at our stores during the first six hours of sales last Friday,” Wal-Mart spokeswoman Sarah Clark said.

But Paul Blank, campaign director at Wake Up Wal-Mart, said, “What this polling indicates is that Wal-Mart’s reputation is in a tailspin.” He said changes in behavior would follow if consumer’s opinions about Wal-Mart continue to fall.

Wal-Mart said the survey was questionable and argued that November sales and an onslaught of holiday shoppers the day after Thanksgiving showed it remained popular.

Figures released Thursday showed that sales at Wal-Mart stores open at least a year rose 3.8 percent in November when compared to November 2004 — close to analysts’ expectations of 4 percent. Same-store sales are considered the best indicator of a retailer’s health.

Retail analyst Don Gher said Wal-Mart’s monthly sales growth did not suggest that shoppers were staying away amid a slew of attacks by groups alleging that Wal-Mart’s low prices come at the cost of poor treatment for its workers, suppliers and communities.

“At this point the sales numbers wouldn’t seem to indicate a backlash,” said Gher of Coldstream Capital Management in Bellevue, Wash. The company has Wal-Mart stock as part of the roughly $900 million in assets it manages.

McShane, a Springfield, Mo., housewife, once spent $600 to $700 a month at Wal-Mart — relying on the world’s largest retailer for everything from groceries to oil changes.

“We cut off Wal-Mart cold turkey. Now I’m preaching it to other people,” McShane said.

Butler, a chicken plant worker from Alpena, said complaints that Wal-Mart is bad for America won’t stop him from shopping there.

“It doesn’t change my mind. It’s just a convenience. And anywhere else costs more,” Butler said outside the Berryville Wal-Mart Supercenter where he had just purchased batteries.

The Wake Up Wal-Mart figures came from two national telephone surveys of about 1,000 adults in January and November. The January 15-20 poll by Lake, Snell & Perry had a margin of error of 3.1 percentage points, and the November poll by Zogby had a margin of error of 3.2 percentage points.

The number of people who said they viewed Wal-Mart very favorably or somewhat favorably fell 18 percentage points to 58 percent while the number who answered that their view was very or somewhat unfavorable increased by the same amount to 38 percent.

The group said attitudes were starting to change shopping practices. Asked how often they plan to shop at Wal-Mart in the next month, the number who said they would not go at all rose 8 percentage points to 28 percent. The largest group, those who planned to shop there once or twice, fell 7 points to 32 percent.

Clark said Wal-Mart does its own internal tracking of consumer sentiment, but declined to release that data. She said the questions were not the same as Wake Up Wal-Mart’s poll so they wouldn’t be comparable.